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by cloverich 855 days ago
It definitely hiccups in high traffic times, but in practice it works reasonably well around the country. Its generally not meant for high volume intersections, where you'd expect a light instead. For perspective, I'd imagined roundabout and other designs as better, but hadn't really considered an alternative algorithm for people to follow.
2 comments
Symbiote 855 days ago
The alternatives outside North America are

1. no markings at all, for very low-traffic places. You're supposed to be driving so slowly that you figure it out. (Yield to the right, if you can't figure it out. In practise, yield to bigger vehicles, pedestrians, cyclists etc — the roads is so small there might not be much choice.)

2. one road is the main road, the other is minor — minor traffic yields. This is most common. There might be signs, but there might only be road markings involving some sort of triangles (i.e. a yield sign).

3. a painted or similar shallow roundabout, showing roundabout rules apply (yield to the left) but allowing large vehicles like buses to drive over the paint. Only used in some countries.

4. an actual (concrete, kerbstone) roundabout, if there's space for that and traffic is higher.

I think you see 3, 1, 1, 2 if you follow this road north-west in Copenhagen: https://www.google.com/maps/@55.6993358,12.5310164,3a,75y,32...

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badpun 855 days ago
Europe has an algorithm that, on such intersections, you have to yield to a car on your right-hand side. This works well until there's a car on every leg of the intersection, which is extremely rare (because, on intersections with such levels of traffic, there are road signs explicitly saying which road has to yield to which one).
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Tagbert 855 days ago
Yes, in the US the rules are like this:

- first to the intersection has the right of way. - if you both arrive at the same time, the one to the right has the right of way. - If you both arrive at the same time facing each other you can both proceed driving straight or turn right. - If you both arrive at the same time facing each other anyone turning left must defer to the other.

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